Mental additions and verbal-domain interference in children with developmental dyscalculia

This study examined the involvement of verba land visuo-spatial domains in solving addition problems with carrying in a sample of children diagnosed with developmental dyscalculia (DD) divided into two groups:(i)those with DD alone and (ii) those with DDand dyslexia. Age and stage matched typically developing (TD) children were also studied. The addition problems were presented horizontally or vertically and associated with verbal or visuo-spatial information. Study esults showed that DD children’s performance on menta lcalculation tasks was more impaired when they tackled horizontally presented addition problems compared to vertically presented ones that are associated to verbal domain involvement. The performance pattern in the two DD groups was found to be similar.The theoretical, clinical and educational implications of these findings are discussed.